Process for the manufacture of polymerization products



1937. QEOHM er AL PROCESS FOR THE MANUFACTURE OF POLYMERIZATION PRODUCTS Aug. 31,

Filed Oct. 16, 1934 i I ,QKEQTOR.

Patented Aug. 31, 1937 raocsss roa 'rns macros! or r01.- arzs'rros rnonoc'rs Otto Riilun and Walter Bauer, Darmstadt, Gerassignors to hm a many, Philadelphia, Pa.

Application October 16 In Germany 1934, October Haas'CoInpaIIy,

Serial N0. 748,472

i 120mm. (CL4s-8l) Q This invention relates to the manufacture of polymerization products. Thus it is applicable to the manufacture of laminated glass as well as to the manufacture of glass substitute.

5 Several processes have been proposed for manufacturing laminated glass using various materials as the intermediate layer, such as cellulose esters, polymerized esters of acrylic acid, etc. and vinyl esters. In some cases, notably with the cellulose esters, a sheet of the ester is fastened to two sheets of glass by means of an adhesive such as gelatin. The polymerized esters mentioned may also be applied in the same way or they may P be dissolved in a suitable solvent, poured on the 10 glass, the solvent evaporated and a second glass sheet combined with the first by means of heat and pressure. Furthermore it has been pro to manufacture laminated glass by polymerizing in situ.

20 In the copending application Ber. No. 748,471 of Otto filed. October 16, 1934, is shown a method for polymerizing unsaturated organic compounds in the form of slabs in such manner that no bubbles are formed in the material durin 25 the polymerization process.

It has also been found-that by modifying this method it can be applied directly to the manufacture of laminated glass.

. The method of the copending application Ber. 30 No. 748,471 consists briefly in polymerizing the terial in narrow preferably vertical cells which are heated evenly over the entire surface of the larger vertical walls, thus avoiding local overheating and the consequent formation of bubbles.

may be made directly from the glass sheets which are to be joined together by a reinforcing or laminating layer. I

This is done in the following manner:-- A thin, narrow strip of an elastic material is flat surface of a to form a low ridge. If the glass is square or rectangular, three sides mm prepared and 5 if of a circular or elliptical shape, the strip of elastic material is not fastened around the entire edge but a small space is left. A second glass sheet of the same size is now laid on the first in firmly to the 50 strips of elastic material. In this way there is formed a narrowcell, the main walls of which are formed by the glass.

The material to be polym into this cell. Theopening may also be closed as as far as suitable to avoid evaporating of the liquid,

for instance with paper. The material is then heated tothe requiredtemperature for a period of time necessary to complete the polymerization. when the polymerization is completed a strong. well-stuck laminated glass is obtained. 5

The process may also be carried out in the following mannert- Thin discs corre nding in thickness to about the final thickness of the laminating layer are fastened to a gins plate. These discs are made of a plastic material, preferably of the polymer of the liquid which is to be subsequently P W, merized betweenthe glass sheets. An adhesive. preferably a solution of the material of which the discs are made may be used to effect a firm joint.

A second 'glass sheet of the size of the first is then laid upon the discs and fastened thereto by the same adhesive.

The edges of the assembly are then closed by fastening a strip of paper or other suitable material to the edges of the glass. leaving an openin through which the material to be polymerized may be po The glass cell and its contents are then heated to effect polymerization.

During polymerization a contraction in the volume of the material takes place. Since the material adheres firmly to the glass this contraction will draw the glass sheets closer together,

4 thus exerting a pressure on the strips or discs of theplastic material which causes them to flow slightly, thus compensating for the reduction in volume and preventing the material from pulling away from the glass. Thus it is necessary to make the strips or discs slightly thicker than the desired final thickness of the laminating layer.

This'can be accurately done and is of advantage in the preparatibn of compound lenses where the layer joining the two glass lenses must be of a definite uniform thickness.

This process is illust ted in the drawing in 40 which g Fig. 1 is a plan view of square sheets of glass with a marginal strip of plastic material;

Fig. 2 is a cross-section on line II-11 of Fig. 1;

Fig. 3 is a plan view of circular glass sheets with a marginal strip:

Fig. 4 is a crosstion on line IV-IV of Fig. 3, and Fig. 5 is a plan view of two sheets of glass with spacing discs and paper lined ed e Referring to the drawing Figs. 1-4, two sheets 2 of any d are held together by a marginal strip 3 of plastic material. If the sheets are rectangular as in -1"ig. 1 the upper edge is left open and if round as in Fig. 8, the stri does not completely close 5.

leaving an opening 4, through which the liquid to to the discs. A strip of paper is then fastened be polymerized may be poured. by means of glue or other adhesive around three Fig. 5 illustrates the method when two glass edges of the glass, forming a cell. Monomeric sheets 5 are fastened together by plastic discs 6 ethyl methacrylate containing a small amount of 6 and the edges. sealed with strips of paper I. benzoyl peroxide is now poured in until the cell Round glass sheets may also be used in this is filled. Itisthen heatedin apreferably vertical method. position at 7080 C. until polymerization is The strips and discs may be of any desired complete. thickness depending onthe use to which the fln- The heating of the glass cell and its contents 10 ished product is to be put. For ordinary safety can be conveniently carried out in the apparatusv glass 0.3 to 1.0 mm. is satisfactory. The strips described in the copending application Ser. No. may be about 0.5 cm. wide and the discs 0.5 to 1.0 748,471 in which the glass cell is placed between cm. in diameter, although these dimensions may the vertical heating units, thus insuringuniform be varied according to circumstances and still be heating of the entire surface of the glass and of within the scope of the invention.

The materials which may be polymerized bebles in the laminating layer during the polymertween glass sheets as described above include ization is entirely avoided. polymerizable unsaturated organic compounds The process is also applicable toother materials such as the esters of acrylic and methacrylic which are capableof being hardened by heat as monomeric material before pouring it between applied to the manufacture of glass substitute as the glass sheets. Mixtures of the above matedescribed in the copending application Ser. No. rials may also be used. Preferably the material 748,471. To this eiiect two sheets of suitable mais heated for a short time to a temperature near terial for cell walls are used such as metal orv i the boiling point of the monomer before the glass sheets, the sides of which are closed by a polymerization takes eflect. marginal strip of elastic material which gives way The plastic material used for the strips or as described above. The walls may also be held discs is preferably a polymer of the same material apart by spacing blocks. The compound to be polymerized so as to serve as glass substitute is 3 polymerization is complete, the entire intermedipoured into the cell where the polymerization ate layer is homogeneous. Instead of the polymer takes effect. other materials may be used which are elastic As far as the manufacture of glass substitute in and somewhat plastic such as India rubber. paper metal or glass molds is concerned, only certain I or gelatin, especially together with softening of the compounds given above for use as layers agents. The India rubber should not contain any for laminated glass are suitable. Only those comsubstances preventing the polymerization. The pounds can be used which alone pr with addimarginal strips described my be replaced by tional substances do not stick to the cell walls unsmall spacing blocks at the edges of the glass der given circumstances, for instance, under the sheets which hold the sheets apart and by a strip influence of cold air or. cold water, so that the 40 of paper which overlaps and is glued upon the products can be removed. such compounds are. outsides of the sheets around the edges so as to for instance, styrol, esters of methacrylic acid make a closed cell. e such as methyl ester, ethyl ester. buty s h following examples will illustrate the alone orasjoint polymerization products'containprocess but are not' intended to limit it as to lug these compounds. As in the manufacture of 45 materials used or conditions of polymerization. laminated glass softening agents may be added, to Example 1.-A strip of polymerized material a considerable extent if suitable. and coloring or obtained by polymerizing a mixture of 85 parts darkening matter and catalysts. substances regphthalate and a small amount of benzoyl peroxide for instance aldehydes. oil of turpentine, collo- 50 and 0.5 cmjwide. A second sheet of glass is ether. cellulose triacetate andcellulose tripropi- P d on the trips and fastened thereto by the onate. For the manufacture of polymerization 5| same adhesive. f A mixture of the monomeric products it is to be noted that the polymerization 6o .ents are then heated to 80' 0., keeping the cell plcted at a temperature, at least 5 to 30'0. bepreferably in a vertical position with the open neath the boiling point. For most compounds dge on top until polymerization is complete. a temperature of (Ia- C. has been found Emmple 2. A mi of 50 parts of ethyl advantageous. methacrylate, 25 parts of methyl acrylate' and 25 Example L-To ethyl methacrylate is added a 65 parts of isobutyl phth alate is used to make'tha' mu amount ofbenmyl peroxide. This mixture 66 polymer for the strips and to fill the space beis heated 5' minutes to C. and then poured tween the glass sheets as described in Example 1. into a cell 5 mm. wide, the main walls consisting trample 3.Ithyl' methaery'late is polymerized of two tangular plates of metal three sides of in the form ofroundrodsinthepresenceofa whichareelosedbyastripofpolymerlzed mate- 70 mall amount of-bcnzoyl peroxide. The rod is rial of the named which is 0.5. mm. 70

then cut intodiscs 0.5 mm.-thick. These'are fasthick and 5 mnnwide. In this cell the mixture tened at appropriate intervals to a glass heets is heated to 70' 0. until polymerization is comby means of a solution of polymer-ind'cthyl plete. Afteroding a slab 5 mm. thickis obmethacryiate and a sccondsheet of glaof the tained.

amesiaeis-intm-nrastenedinthelameway Iminpu5. 'llo74.5partsofmethyleste oru the space between the glass sheets with a polymethacrylic acid 25 parts of butyl ester of phthalic acid and 0.5 parts of neats-foot oil and a small amount of benzoyl peroxide are added. s mixture is poured into a cell 10 mm. wide, 5 the main walls consisting of two rectangular sheets of glass three sides of which are closed by paper. The sheets of glass are held apart by means of small spacing blocks at the edges consisting of a mixture of '10 parts of gelatin and 30 parts of glycerin. The fourth side is then also closed with paper. In this cell the mixture is heated for minutes to 90 C. and further for to 30 hours to 75 C. until polymerization is complete. The cell is then placed in cold water. 15 After some time the polymerization product may be easily removed. a

Example 6.-50 parts of ethyl methacrylate and 50 parts of methyl methacrylate anda small amount of benzoyl peroxide are poured into a cell and treated as described in Example 5.

Example 7.-80 parts of methyl methacrylate and 18 parts of vinyl acetate and 2 parts of mineral oil and a small amount of benzoyl peroxide are poured into a cell and treated as described in' Example 5.

We claim:-

1. The process for the manufacture of laminated glass comprising uniting two sheetsof glass by means of a marginal strip of an elastic polymer of an ester of the group consisting of acrylic and methacrylic acids, filling the space between the sheets of glass with an ester of the same group andheating the whole in a preferably vertical .position to effect polymerization of said ester.

2. Process for the manufacture of laminated glass comprising uniting two sheets of glass by I means of a marginal strip of a joint elastic polymer of at least two esters of the group consisting of acrylic and methacryiic acids, filling the space between the sheets of glass with a mixture of at least two esters of the same group, and

heating the whole. in a preferably vertical position to effect polymerization of said esters.-

3. The process for the manufacture of laminated glass comprising uniting two sheets of glass by means of a marginal strip of a joint elastic polymer of ethyl methacrylate and methyl acrylate, filling thespace between the sheets of glass with a mixture of ethyl methacrylate and methyl acrylate and heating the whole in a preferably vertical position to effect polymerization of said esters.

4. The process for nated glass comprising uniting two sheets of glass 55 by means of amarginal strip of a polymer of methyl methacrylate, filling the space between the sheets of glass with methyl methacrylate and heating the tion to effect polymerization of the methyl g0 methacrylate.

5. The process of glass comprising uniting two sheets of glass by means of a strip of paper whichoveriaps and is glued upon the outside of the glass sheets around 55 the edges but leaving an sheets being held apart ,by spacing blocks consisting of gelatin with softening agents, filling an estaof the joint polymer of the manufacture of lamiwhole ina preferably vertical posimanufacturing laminatedopen space, the two merizable ester of an acid of the group consisting of acrylic whole to effect the polymerization of said ester.

6. The process of manufacturing laminated glass comprising means of spacing group consisting of acrylic and methacrylic acids, sealing the edges of the assembly but leaving an open space, filling the space between the glass sheets with an ester of the tion of said ester.

'7. The process oiv manufacturing laminated glass comprising uniting two sheets of glass by means of spacing blocks of a plastic joint polymer of at least two esters of the group consisting of acrylic andmethacrylic acids, sealing the edges of the ms'embly but leaving an open space, filling the space between the glass sheets w th a. mixture of at least two esters of the same group and heating to effect the polymerization of said esters.

8. The process of manufacturing 1 glass comprising uniting means of spacing blocks comprising a plastic ethyl methacrylate and methyl acrylate, sealing the edges of the assembly but leaving an open space, filling the space between the glass sheets with a mixture ofethyl methacrylate and methyl acrylate and heating the whole to effect the polymerization of said esters. 9. The process of manufacturing laminated glass comprising uniting two sheets of glass by means of spacing blocks comprising a plastic polymer of methyl methacrylate, sealing the edges of the assembly butv leaving an open space, filling the space between the glass sheets with methyl methacryiate, and heating the whole to effect the polymerization of said ester.

10. The process of manufacturing glass which comprises inserting between two sheets of glass relatively thin spacing elements of a polymerized ester of an acid of the group consisting of acrylic and methacrylic acids, filling the space between the glass sheets with the manomeric form of said ester, and subjecting-the same to polymerizing influences.

11. The process of manufacturing laminated glass which comprises inserting between two sheets of glass relatively thin spacing elements of a polymerized ester of an acid of the group consisting of acrylic and methacrylic acids, fllling the space between the glass sheets with the monomeric form of said ester,- and heating the wieole to effect polymerization of said monomeric es er. r

and methacrylic acids and heating the.

uniting'two sheets of glass by blocks of a plastic polymer of:

' same group and heating to effect thepolymeriza- 12. The process of manufacturing laminated glass which comprises inserting between two sheets of glass relatively'thin spacing elements of a polymerized mixture of ethyl methacrylate and methyl acrylate, filling the space between the glass sheets with the monomeric form of said- 

